Northern C et al. (1988) Parasite Immunol "Western blot analysis of reactivity to larval and adult Strongyloides ratti antigens in mice."

Northern C, Grove DI

[Parasite Immunol, 1988]

Mice were infected once, twice or many times with Strongyloides ratti infective larvae, and the parasite was allowed to complete its development. Other mice were infected many times with either infective larvae only, by aborting the infection with cambendazole, or with adult worms transferred by intra-oesophageal intubation. Sera from these animals were analysed by immunoblotting against SDS-PAGE separations of larval and adult worm water-soluble, deoxycholate-soluble, sodium dodecyl sulphate-soluble and excretory/secretory antigens. Minimal antibody responses were observed after primary and secondary infections. Mice exposed to multiple complete infections reacted strongly to both larval and adult antigens but greater responses were observed against the larval preparations. Stage-specific effects were noted in mice infected with larvae only or adult worms only. Mice exposed only to larvae reacted with larval antigens and to a minor degree to somatic adult worm antigens while those mice which were exposed only to adult worms failed to react with any of the antigen preparations. Some cross-reactions were found, however, as mice infected only with larvae displayed strong reactions against both larval and adult excretory/secretory products. These data demonstrate differences in sero-reactivity to infective larvae and adult worms and suggest that humoral immunity is induced by larvae migrating through the tissues and not by adult worms in the gut.

Northern C et al. (1989) Clin Exp Immunol "Surface labelling of Strongyloides ratti: stage-specificity and cross-reactivity with S. stercoralis."

Northern C, Grove DI, Warton A, Lovegrove FT

[Clin Exp Immunol, 1989]

Various methods of radioiodination were compared for their efficacy in labelling the surface of Strongyloides ratti infective larvae and adult worms. The Iodogen method was chosen as the optimal technique for this parasite. The surface location of 125-iodine was confirmed with light microscope autoradiography of transverse sections of labelled worms. Stage-specific surface components were identified when the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) profiles of infective larvae and adult worms were compared. Labelled surface molecules were solubilized with either the non-ionic detergent Triton-X-100, the anionic detergents sodium deoxycholate (DOC) or sodium dodecyl sulphate (SDS), or the cationic detergent cetyl trimethyl-ammonium bromide (CTAB). The CTAB extract yielded most labelled proteins that retained their antigenicity in an immunoprecipitation assay with hyperimmune mouse sera. Immunoprecipitation analysis with stage-specific mouse sera revealed that the surface of infective larvae is immunogenic and that there are no cross-reactions with adult worms. Adult worms resident in the intestine were not found to be immunogenic and showed a complete absence of reactivity. Antigenic determinants shared between S. ratti and S. stercoralis were identified. Patients infected with S. stercoralis precipitated bands with molecular weights 32 and 34 kD which were not reactive with normal sera. These reactions suggest the potential usefulness of the surface of S. ratti as a source of diagnostic antigens.

Ketting RF et al. (2006) CSH Protoc "Detection of si/miRNA in C. elegans by Northern Blot."

Tijsterman M, Plasterk RH, Ketting RF

[CSH Protoc, 2006]

Grove DI et al. (1987) J Parasitol "Oral transfer of Strongyloides ratti adult worms to mice."

Grove DI, Northern C

[J Parasitol, 1987]

Long T et al. (2017) Methods Mol Biol "Northern Blot Detection of Virus-Derived Small Interfering RNAs in Caenorhabditis elegans Using Nonradioactive Oligo Probes."

Long T, Lu R

[Methods Mol Biol, 2017]

Northern blot analysis has been widely used as a tool for detection and characterization of specific RNA molecules. When coupled with radioactive probe northern blot allows for robust detection and characterization of small RNA molecules of trace amount. Here, we describe the detection and size characterization of virus-derived small interfering RNAs (vsiRNAs) in C. elegans using nonradioactive DNA oligo probes in northern blotting. Our protocol allows for the detection and characterization of not only primary vsiRNAs but also secondary vsiRNAs, a class of single-stranded vsiRNAs that has distinct migration pattern, and can be easily adapted to the detection of vsiRNAs in other organisms.

Grove DI et al. (1985) Aust J Exp Biol Med Sci "Interactions of Strongyloides ratti free-living and skin-penetrated infective larvae and parasitic adults with serum and cells in vitro."

Grove DI, Northern C, Dawkins HJ

[Aust J Exp Biol Med Sci, 1985]

When Strongyloides ratti free-living infective larvae were incubated with peritoneal exudate cells from normal or previously infected mice, cell attachment occurred only in the presence of normal (NMS) or immune mouse serum (IMS). This non-specific effect was transitory with larvae being alive and free of cells 24 h after incubation. Cell attachment was mediated by complement. When incubated with infective larvae which had penetrated mouse skin, both normal and immune cells attached to larvae in the absence of serum. This effect was again transitory except when immune cells or immune serum were present, indicating a specific immunological mechanism. Again, larvae remained viable. When incubated with isolated parasitic adult worms, persistent cell attachment occurred in the presence of immune serum, immune cells or both, but all worms remained viable. This system provides a means for investigating the mechanisms of resistance to reinfection in strongyloidiasis.

Grove DI et al. (1987) J Parasitol "Electron microscopical studies of Strongyloides ratti infective larvae: loss of the surface coat during skin penetration."

Papadimitriou JM, Grove DI, Warton A, Northern C

[J Parasitol, 1987]

Previous indications using radiolabelled larvae that Strongyloides ratti free-living infective larvae lose a surface coat during penetration of the skin were further investigated by transmission electron microscopy of the cuticle of S. ratti infective larvae in the free-living stage, after penetration of mouse skin, and after migration to the lungs. These studies demonstrated the presence of a faint electron-dense surface coat external to the epicuticle on free-living worms which was absent from larvae recovered from the skin and lungs. When free-living infective larvae were incubated in 10% CO2 at 37 C and then examined with phase-contrast microscopy, worms were observed in the process of losing this coat. These observations confirm the hypothesis that S. ratti infective larvae lose a surface coat during penetration of the skin.

Cutter AD et al. (2006) Genetics "Patterns of nucleotide polymorphism distinguish temperate and tropical wild isolates of Caenorhabditis briggsae."

Barriere A, Charlesworth D, Felix MA, Cutter AD

[Genetics, 2006]

Caenorhabditis briggsae provides a natural comparison species for the model nematode C. elegans, given their similar morphology, life history, and hermaphroditic mode of reproduction. Despite C. briggsae boasting a published genome sequence and establishing Caenorhabditis as a model genus for genetics and development, little is known about genetic variation across the geographic range of this species. In this study, we greatly expand the collection of natural isolates and characterize patterns of nucleotide variation for six loci in 63 strains from three continents. The pattern of polymorphisms reveals differentiation between C. briggsae strains found in temperate localities in the northern hemisphere from those sampled near the Tropic of Cancer, with diversity within the tropical region comparable to what is found for C. elegans in Europe. As in C. elegans, linkage disequilibrium is pervasive, although recombination is evident among some variant sites, indicating that outcrossing has occurred at a low rate in the history of the sample. In contrast to C. elegans, temperate regions harbor extremely little variation, perhaps reflecting colonization and recent expansion of C. briggsae into northern latitudes. We discuss these findings in relation to their implications for selection, demographic history, and the persistence of self-fertilization.

Kawano T et al. (1996) Biochem Biophys Res Commun "Molecular cloning of a cDNA for the glutamate transporter of the nematode Caenorhabditis elegans."

Kawano T, Takuwa K, Nakajima T

[Biochem Biophys Res Commun, 1996]

We cloned a cDNA for the glutamate transporter of the nematode Caenorhabditis elegans. The nucleotide sequence and Northern blotting indicated that the glutamate transporter gene is transcribed as a polycistronic mRNA in C. elegans and that subsequent trans-splicing yields two distinct monocistronic mRNAs for the glutamate transporter and the ATP synthase c subunit, respectively. The yields of these monocistronic mRNAs were quite different, suggesting that glutamate transport in C. elegans is regulated in the post-transcriptional phase. The glutamate transporter of C. elegans shows about 50-60% sequence similarity with those of mammals. This is the first description of invertebrate glutamate transporters.

Grillet ME et al. (1994) Ann Trop Med Parasitol "Vector competence of Simulium metallicum s.l. (Diptera: Simuliidae) in two endemic areas of human onchocerciasis in northern Venezuela."

Grillet ME, Basanez MG, Botto C, Barrera R

[Ann Trop Med Parasitol, 1994]

Experimental infections of Simulium metallicum s.l. with Onchocerca volvulus were carried out in two onchocerciasis foci, Altamira and Trincheras, in northern Venezuela, to determine vector competence. Wild-caught flies, fed on infected volunteers, were maintained in the laboratory for 13-15 days at 27 degrees C. Parasite development was complete but asynchronous and retarded. No differences in the vector competence of the two populations of S. metallicum s.l. were found. However, a less efficient development of the parasite occurred during the dry season at both localities. The distribution of the parasite within the vector was aggregated and also displayed seasonal variation. The seasonal susceptibility may be a consequence of a density-dependence regulation mechanism of the parasite within the vector. These results indicate a relatively low vector competence for S. metallicum s.l. in northern Venezuela.